The objective of this proposal is to establish the role of cervicovaginal antibody in determining enterobacterial colonization of the introital mucosa of the vaginal vestibule in women with recurrent urinary infections. Longitudinal studies of women subject to re-infections of the urinary tract will include antibody measurements of their serum, cervicovaginal fluid, and salivary fluid, using a radioimmunoassay for quantitating bacterial antibody. The specificity of the cervicovaginal antibody will be studied by exposing different strains of the Enterobacteriaceae family to cervicovaginal antibody. The variation imposed by the menstrual cycle on cervicovaginal antibody directed against Enterobacteriaceae will be studied in controls and susceptible women by frequent collections of cervicovaginal fluid throughout the menstrual cycle. The variation in bacterial adherence among different O-groups of E. coli is likely due to bacterial fimbriae. The degree of bacterial adherence will be compared to the amount of hemagglutination of each strain (as a measure of bacterial fimbriae) as well as whether anti-fimbrial antibody in rabbits will prevent in vitro bacterial adherence after exposure of the bacterial strain to the antibody.